Air-break electric switch and operating electromagnet therefor



Oct. 8, 1929. w, OKEEFFE AIR BREAK ELECTRIC SWITCH AND OPERATING ELECTROMAGNETS THEREFOR .Filed. May 19, 1928 70 621 ZOif Patented Oct. 8, 1929 UNITED STATES PATENT OFFICE GEORGE W. OK EEFEE, OF MILTON, MASSACHUSETTS, ASSIGNOR T0 CONDIT ELECTRI- CAL MANUFACTURING CORPORATION, OF SOUTH BOSTON, MASSACHUSETTS, A COR- .PORATION OI MASSACHUSETTS AIR-BREAK ELECTRIC SWITCH AND OPERATING ELECTROMAGNET. THEREFOR Application filed May 19,

This invention relates to air break electric switches especially adapted for motor starting service. i

In such a switch the sets of separable contact members that are associated with the various phases of the multi-phase circuit are isolated from each other by insulating barriers, or are chutes, which are arranged to prevent the arcs formed upon the separation of the contact members under load from intermingling and short cireuiting the switch. The are chute is one of the essential elements of the switch and it is not intended that the switch should be operated without the are chute. The are chutes are generally removable so that access to the contact members can be gained readily for the purpose of inspecting, cleaning and adjusting the contact members. It frequently happens that a workman fails to replace the arc chutes in position after he has overhauled the switch. Consequently, the circuit interrupting arcs are free to commingle when the switch is opened under heavy load. Serious damage can thus occur.

It is an obpect of the present invention to provide an electric switch of the type above set forth with improved means to prevent the operation of the switch when the arc chute is not in proper posi ion.

The switch of the type above set forth is usually electrically operated and has a holding coil which maintains the switch closed for so long as the coil'is normally energized.

A further object of the present invention is means to disable the holding coil and prevent its effective operation when the arc chutes are not in proper position.

A further object is generally to improve the construction and operation of electric switches.

Fig. 1 is a front elevation of an electric switch embodying the present invention with the cover of the enclosing casing removed.

Fig. 2 is a section taken along line 22 of Fig. 1.

Fig. 3 is a perspective view of the removable are chute or housing which encloses the sets of cooperating contact members.

Fig. 4 is a circuit diagram of the connec- 1928. Serial No. 279,140.

tions between the holding coil of the electromagnet and arc-chute controlled circuit-controller ot' the electro-magnet.

The electric switch embodying the present invention includes an enclosing casing formed of two complementary parts. The part 10 comprises a support for the switch and the part 12 is removable and comprises a cover for the casing. The switch is supported on a plate 13 located within the casing and secured to the part 10 thereof. -r

The switch here shown is of the three phase type and is provided with three sets of ,stationary contact members 14 which are secured in spaced horizontal alignment to the upper portion of the supporting plate 13. Cooperating movable contact members 16 are supported on spring urged carriers 18 that are pivotally supported on an insulating bar 20. Said bar is secured to the arms of a bifurcated bar 22 that is attached to the armature 24 of a switch operating electro-magnet 26 carried by the supporting plate 13 at the lower portion thereof. Said armature 24: is pivoted in front of the pole faces of the electro-magnet on a pivot pin 27. The electromagnet is provided with an actuating coil 28 that is adapted to be maintained energized to hold the switch closed. The movable contact members and associatel operating mechanism are adapted to move by gravity in a counterclockwise direction into a switch open position.

The sets of cooperating contact members are enclosed in an arc chute or housing 30 which is formed of insulating material and has a plurality of contact compartments 82, see especially Fig. 3, in each of whicha separate set of contact members are located. The are chute is located removably in the position illustrated in Fig. 2 and has vertical slots 34:

in its end walls in which upstanding projeccontrolled by the arcing chute are provided to control the energization of the actuating coil 28 of the electro-magnet. Said means as here shown comprises a circuit controller ar ranged in series with the electro-magnet as shown in Fig. 4. Said circuit controller comprises a movable resilient contact member 38 and a cooperating and also preferably resilientstationary contact member 40. Said contact members are located in'unediately under one of the partition walls 42 between the compartments 32 of the arc chute. Said wall 42 is adapted to bear upon the upper con tact member 38, and by the weight of the arc chute, to maintain it in engagement with the cooperating contact member for so long as the arc chute is in operative position. The circuit through the coil 28 is thus complete, within the switch casing, and can be controlled in the usual manner.

When, however, the arc chute is removed, the contact members separate by their own resiliency, the contact member 38 moving into the dotted line position illustrated in Fig. 2. The circuit through the actuating coil 28 is thus broken and consequently the switch can not be closed until the are chute is restored to its operative position.

My concurrently filed application Serial No. 279,138 shows and claims broadly means controlled by the removable arc chute for preventing the closing of the switch. 7

I claim:

1. An electric switch having stationary and movable contact members, an arc chute removably located in cooperative position with said contact members, switch operating mechanism including an electro-magnet having an actuating winding, and means under control of said arc chute for governing the energization of said winding.

2. An electric switch having stationary and movable contact members, an arc chute removably located in cooperative position with said contact members, switch operating mechanismincluding an electro-magnet having an actuating winding, and means under control of said arc chute for governing the energization of said winding, arranged to prevent the energization of said winding when said arc chute is removed from its aforesaid position.

8. [in electric switch having stationary and movable contact members, an arc chute removably located in cooperative position with said conta ct members, switch operating mechanism including an 'electro-magnet having an actuating winding, and a circuit controller for said winding controlled by said are chute.

4. An electric switch having stationary and movable contact members, an arc chute removably located in cooperative position with said contact members, switch operating mechanism including an electro-niagnet having an actuating winding, and a circuit controller for said wint g controlled by said arc chute and located in the thereof.

5. An electric switch having stationary 'and movable contact members, an arc chute removably located in cooperative position with said contact members, switch operating mechanism including an electro-magnet having ah actuating winding, and a circuit controller for said winding located in position to be engaged and held in a circuit controlling position by said are chute only when it is in the aforesaid position, whereby to permit energization of said winding.

6. An electric switch having stationary and movable contact members, an arc chute removably located in cooperative position with said contact members, switch operating mechanism including an electro-magnet having an actuating winding, and a circuit controller for said winding located beneath said are chute and having a movable member engaged and maintained in circuit controlling position by said arc chute when the latter is in the aforesaid position, said movable member being movable away from a circuit controlling position when said are chute is removed, whereby to prevent energization of said winding.

In testimony whereof, I have signed my name to this specification.

GEORGE W. OKEEFFE.

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